This invention relates to the field of receptacle valve assemblies and more particularly to the field of valve assemblies for cryogenic fluids including liquified natural gas.
With the advent of liquified natural gas (hereafter "LNG") as a fuel for vehicles, a necessity has arisen to provide for relatively quick fueling of vehicles. It should be noted that the LNG used to fuel vehicles typically comprises approximately 99% methane, a higher percentage of methane than is present in unrefined liquified natural gas. A limiting factor in conventional fueling operations is the speed and safety by which liquified natural gas may be transferred from storage tanks to vehicle tanks. The limitations result in large part from the temperatures, typically below zero (-259.degree. Fahrenheit), at which the fueling of vehicles is accomplished and from the volatility of LNG vapors. Hoses and couplings are conventionally used in the transfer of LNG.
Existing couplings incur problems when receptacle valve components shrink due to extreme temperature reduction as LNG flows through the coupling. Leakage around the seal and formation of ice from water vapor may result. In some applications, ice ultimately freezes the connection preventing the operator from disconnecting the fuel coupling until the coupling thaws.
Adaptation of known and commercially practical valve assemblies to the requirements of LNG fueling have not been fully successful due to the extreme temperature variations imposed on valves and seals.
A summary prepared by Houston Metropolitan Transit Authority ("Houston Metro") based on its survey of fueling couplings indicates that current designs for a less hazardous, yet relatively quick transfer fuel coupling design include products developed by Gibson Technical Services, Cryopak, Minnesota Valley Engineering, and Parker Hannifin. A synopsis of a summary made by Houston Metro follows:
a. The Gibson design involves a coupling using a bayonet connection for the female dispenser which is attached to the end hose and slides over the male receptacle on the vehicle. TEFLON o-rings and dynamic face seals secure the connection. Liquid flows through the inner orifice into the vehicle's fuel tank while methane vapor is removed from the annular space of the outer orifice space.
b. The Cryopak design involves a fuel coupling shaped similar to a common gasoline fuel nozzle with the exception that two parallel orifices extend from the handle. One orifice delivers LNG and the other orifice retrieves vapor.
c. Minnesota Valley Engineering couplings are designed to be connected with a quarter turn rotation. In-line poppet valves open upon contact allowing liquid to flow.
d. Parker Hannifin and Minnesota Valley Engineering have developed a fuel coupling designed to be connected with a quarter turn rotation. The operator opens in-line poppet valves with a manual lever, which lever cannot be actuated unless the coupling is securely connected. Parker Hannifin Corporation product bulletin for Part No. 1169-61 discloses a form of valve receptacle.
The following U.S. Patents offer insight as to the art of fuel transfer valves although the disclosures are not designed for cryogenic applications. It should be noted in relation to the art referenced, that the art of valve design is wide spread and prolific.
Laughtner U.S. Pat. No. 3,318,346 discloses a container adapted to contain a combustible gas and adapted to be filled with a combustible gas from a pressurized tank. The container includes an aperture, pressure-responsive non-return valve means comprising a hollow tubular member slidably arranged in the aperture and having end portions respectively located within and without the container for placing the interior of the container in communication with the interior of a pressurized tank. The non-return valve means opens only in response to an increase in the pressure within the hollow tubular member, said hollow tubular member being slidable from a normal inactive position into an active position deeper into the container.
Pichl U.S. Pat. No. 3,295,567 discloses a filling valve of a fuel tank of a gas fuel lighter, said valve comprising a valve housing, a valve body moveable in said housing open between a valve closing position and a valve open position, yieldable means biasing the valve body into its valve closing position, an elastic annular sealing member disposed within the housing opening between the inner wall portion of the housing and the valve body to define an entrance throat for the insertion of a fuel container. The sealing member includes an annular disk having a deformable flange to form an annular seal between the neck and valve body.
Zellweger U.S. Pat. No. 3,085,601 discloses a gas fueled lighter valve including a fixed member, a movable member, and a sealing member and containing two passages, one being an inlet passage for liquified gas and the other being an exhaust passage to put the fuel reservoir in communication with the atmosphere, the valve being actuated by the connecting member of a refill vessel.
Labat U.S. Reissue Pat. No. 26,193 describes a filling arrangement for a liquified gas lighter comprising in combination a supply valve on the gas supply cylinder and a lighter valve in the wall of the tank of the lighter, each valve being spring operated for opening and closing and each provided with a projecting stem, the two stems coming into contact with each other to produce opening of the two valves, the spring of the gas supply cylinder valve being more powerful than that of the lighter valve. The lighter has an escape valve independent of the filling valve.
Brightenstein U.S. Pat. No. 3,035,617 discloses a fuel transfer adapter with dual valve actuator for use in fueling cigarette lighters, comprising a valve actuating adapter stem having a charging port with a pin operated valve located interiorly thereof, for pressurized fuel canisters having a nipple with a concealed valve therein, the adapter comprising a body having a coupling part with a coupling bore adapted to engage the canister nipple and an elongated nozzle extending from said body with a second bore communicating from said coupling bore through the tip of the coupling nozzle. The second bore extends into the nozzle through the outer tip end of the nozzle. A trigger pin is provided in the second bore, said trigger pin having an opposite inner end extending into the coupling bore with a coupling seal provided in the coupling bore. The trigger pin may be shifted longitudinally, the trigger pin being adapted to actuate respective valve means of a lighter and canister to which the adapter is coupled.
Drager, et al. U.S. Pat. No. 3,530,905 discloses a vaporizer for a anesthetic including a filling and emptying means therefore, said filling and emptying means including a cylinder coupling means. The cylinder coupling means is designed for receiving a male coupling connection on a flexible conduit. The coupling means includes a valve activated by the male coupling means.
The existing art does not teach a quick connect, quick fueling, and freeze resistant valve for cryogenic applications providing for efficient, safe transfer of LNG in a commercial application.